What is wrong with my Common Goldfish/Tank?

[Jungwoo]

I have a 1.75 inch common goldfish that started to exhibit some symptoms about 4 days ago. It's dorsal fin remains clamped down, it is developing a thin sunken belly, it is wobbling a bit when it swims and seems to have a translucent film over the back half of its body. The fish eats, but not like it used to. My tank is 12 gallons, acrylic with an Eclipse hood filter. Every week I do a 20%-25% H20 change, vaccum the gravel, change the filter cartridge and change a small Algone bag I keep in the filter. The tank has 3 other small fantails (under 1.5 inches long) that are very healty. My water quality is: PH 7.0, temp 82F, Amonia 0.25 ppm (toxic amonia 0.00165 ppm) and Nitrite 0.05 ppm. We also introduced two medium size, live, broad-leafed plants that seem to be doing fine along with a moss ball. I also added an air-stone 2 days ago thinking that oxygen level might be an issue. The tank has been running for around 5 months. I have studied several fish diseases on line and I suspect it is some type of bacterial infection or parasite brought on by stress, water-quality, etc. Any more specific diagnosis or treatment would be much appreciated. Thanks in advance.

 

[RazorbacksFan]

The fish need a bigger tank it is overstocked, after five months the tank should have no ammonia or nitrite. As far as the issue with the fish a picture would help us diagnose the problem.

 

[jsoong]

Agree that the tank is way overstocked. You may be able to keep 2 fantails in the 12 with lots of water changes, but commons simply don't do well in small tanks.

The fact that you still have ammonia & nitrites in the tank is not good. That is prob due to you not having a large enough biofilter for the occupants. In the short term, you need to do daily water changes to keep those levels in check. A bigger setup is definitely needed if you want to avoid problems. <A pond for the comet, and a 30-40 gal for the 3 fantails.>

I suspect the comet has some kind of internal parasite from your description. However, there is no point treating for it until you get your water parameters under control. <Once you have controlled the water parameters, and found a larger setup for the commet, you might want to treat everyone with a course of Praziquental. This is best done with food containing the drug ... eg. Jungle's anti-parasite food. Prazi is quite safe, even for frys, and many goldfish keepers will prophylactically treat all new goldfish with Prazi during QT.>

 

[Jungwoo]

Thank you for that very helpful reply. The plan was to put the common into my father's 10,000 gallon goldfish pond when he grew a bit bigger. Unfortunately, he died last night. I have concluded (the hard way) that it is virtually impossible to keep the amonia and nitrite levels at zero in the Eclipse 12 with even only 5 to 6 inches of goldfish. We fed sparingly, changed water religiously every 5 or so days, vacuumed, used Algone bags and treated the water with Stresscoat and aqarium salt as directed. More work than that is not worth the trouble. The next step in this hobby for me is probably a 30 gallon glass tank with an oversized Eheim canister filter and a good air stone.

 

[jsoong]

5-6" of goldfish is a lot of fish ... Unlike the typical tropical fish, which is long & thin, goldfish is rotund, so has a lot more mass compared to a tropical of the same length. <A tropical's mass goes up roughly at the square of the length, a fat fish like the gold goes up with the CUBE of the length, so it is easy to overload the tank.>

For now, just do lots of water changes until you get a bigger tank. When I cycled in a 10 gal with 2 small fantails, I was doing 50% pwc every other day!

 

[Jungwoo]

Thanks. As you can see from the pics, the 3 fantails I have in there now are very small. I did a mid-week water change last Wednesday of about 40% along with a thorough gravel vacuum and will do the same today. Amonia levels have dropped to 0.0005 ppm as have the Nitrates to alost 0.0 as of today, but I noticed that my PH today was down from its usual 7.0 to around 6.6. Also, today one of the oldest fantails in the tank developed a redish patch behind it stomach (which can be seen from both sides of his body. It is very difficult to keep a tank of this size stable and now it looks like I have another sick fish.

 

[DizzCat]

Every week I do a 20%-25% H20 change, vaccum the gravel, change the filter cartridge and change a small Algone bag I keep in the filter.

I am surprised no one caught this. This is the reason why you cannot get your ammonia down, you have not cycled the tank at all if this is what your doing. The good bacteria that eats the ammonia lives in the filter cartridges and sponges in the filters. You should only change it out after a few months, and then make sure to keep a piece of the old on in until the new one develops a good bacteria colony. You know how old filter media gets so gross and gunky? That is the stuff that keeps a tank healthy. If you need to rinse the cartridge off, swish it in tank water only, not tap water. Tap water will kill off the colony. After awhile your ammonia should start to go down.

 

[mfdrookie516]

i agree with dizzcat... i keep more than one filter in every tank just mainly for that reason... if you are wanting to keep changing filter cartridges like that, you may want to get a filter with dual cartridges so that one can stay in with good bacteria until the other develops it.. and i would certainly get a bigger tank... goldfish especially produce alot of waste... i had goldfish when i first got my tank, they are hardy for sure, but my water was always testing bad... now that i have tropical fish and cichlids, my water stays much cleaner, and doesnt have the nasty smell it did before...

 

[Jungwoo]

Thanks for this advice. By the way, please take a look at my pics a couple of posts above. Does it really look like I have too many fish in there? It is just the three small fantails. Thanks, again.

 

[mfdrookie516]

ive always been told with goldfish, you need at least 1.5-2 gallons of water for every inch of fish... i would say that with 3 fish at 2" long you are probably pushing it a bit... golfish grow rapidly... i have seen goldfish in ponds that have been 2 feet long... if you dont have too much in it right now, you will for sure soon... you will be really pleased with the outcome if you get a bigger tank... it will be less work and more pleasure... plus the golfish will be much happier having a bigger place to swim... thats just my opinion though

 

[Jungwoo]

Thank you.